Skeletal muscle quality affects patient outcomes in acute type A aortic dissection

OBJECTIVES: Although skeletal muscle quantity is linked to surgical outcomes, quality remains unexamined. In this study, we evaluated whether skeletal muscle quality and quantity could predict surgical outcomes in acute type A aortic dissection (ATAAD). METHODS: Skeletal muscle quality and quantity were evaluated using computed tomography (CT) values and the psoas muscle mass index, respectively. From May 2004 to December 2017, 324 ATAAD patients underwent aortic replacement after CT scans and psoas muscle mass index measurements. Patients were grouped into intramuscular fat (IMF; n = 55) and non-IMF (n = 269) deposition groups. RESULTS: The mean ages of the patients were 72.3 ± 9.7 and 66.8 ± 12.1 years (P = 0.002), and hospital mortality rates were 3.6% (2/55) and 7.4% (20/269; P = 0.393) for IMF and non-IMF deposition groups, respectively. IMF deposition was a risk factor for a deterioration in activities of daily living at discharge by multivariable analysis [odds ratio 0.33, 95% confidence interval (CI) 0.16-0.69; P = 0.003]. The mean follow-up was 43.9 ± 36.8 months. The 5-year survival was significantly worse for the IMF deposition group (IMF 73.8% vs non-IMF 88.2%; P = 0.010). The multivariable Cox proportional hazard analysis showed that IMF deposition significantly predicted poor survival (hazard ratio 3.26, 95% CI 1.47-7.24; P = 0.004), unlike psoas muscle mass index and age. CONCLUSIONS: Skeletal muscle quality, defined by IMF deposition, was an independent predictor of overall survival and postoperative activities of daily living dependence risk in patients undergoing surgery for ATAAD. Thus, IMF deposition may be an additional risk factor for estimating late outcomes of ATAAD surgery.